BLUNT CLONING KITS Download

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BLUNT CLONING KITS
IMPORTANT!
-80°C and -20°C Storage Required
Immediately Upon Receipt
Lucigen Corporation
®
Advanced Products for Molecular Biology
2120 W. Greenview Drive
Middleton, WI 53562
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Tel:
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FAX:
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Email:
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FOR RESEARCH USE ONLY. NOT FOR HUMAN OR DIAGNOSTIC USE
MA004 v11.3
CLONESMART® Blunt Cloning Kits
Technical Support
Lucigen is dedicated to the success and satisfaction of our customers. Our products are tested to
assure they perform as specified when used according to our recommendations. It is imperative that
the reagents supplied by the user, especially the DNA targets to be cloned, are of the highest
quality. Please follow the manual carefully and contact our technical service representatives if
additional information is necessary. We encourage you to contact us with your comments regarding
the performance of our products in your applications. Thank you.
Notice of Limited Label License, Copyright, Patents, Warranties, Disclaimers and
Trademarks
Copyright© 2001-2004 by Lucigen Corp. All rights reserved. UltraClone, CloneDirect, pcrSMART, pEZ, pEZSeq,
cSMART, PCR-SMART, and Replicator are trademarks of Lucigen Corp. Lucigen, CloneSmart, ClonePlex,
DNATerminator, E. cloni, PCRTerminator and pSMART, CopyRight, and NanoClone are registered trademarks of
Lucigen Corp. HydroShear® and GeneMachines® are registered trademarks of GeneMachines Corporation (San
Carlos, CA). Vent is a trademark of New England Biolabs, Inc. DH10B and DH5 are trademarks of Invitrogen Corp.
Lucigen’s products are sold for research use only and are not to be used in humans or for medical diagnostics.
Lucigen’s liability with respect to any CloneSmart product is limited to the replacement of the product. No other
warranties of any kind, expressed or implied, including without limitation, any implied fitness for any particular use,
are provided by Lucigen. Lucigen is not liable for any direct, indirect, incidental or consequential damages arising out
of or in connection with the use or inability to use any of its CloneSmart products.
Limited Label License
This product is the subject of U.S. Patent #6,709,861 and pending patent applications owned by Lucigen Corporation.
The consideration paid for this product grants a Limited License to use the product pursuant to the terms set forth in
this Limited Label License. Academic, Not-for-Profit and For-Profit institutions acquire certain limited nontransferable
rights with the purchase of this product (see below).
The purchase price of this product includes limited, nontransferable rights to use only the purchased amount of the
product to perform CloneSmart Blunt Cloning Technology and only as described in CloneSmart Blunt Cloning Kit
Instruction Manual. This limited license specifically excludes manufacture of the pSMART vector or derivatives
thereof. Lucigen Corporation reserves all other rights; in particular, the purchaser of this product may not transfer or
otherwise sell this product or its components or derivatives to a third party, and no rights are conveyed to the
purchaser to use the product or its components or derivatives for commercial purposes. “Commercial purposes”
includes any activity for which a party receives consideration and may include, but is not limited to, (1) use of the
product or its components or derivatives in manufacturing, (2) use of the product or its components or derivatives for
diagnostic purposes, (3) transfer or sale of vectors made with the product or components or derivatives of the
product, (4) use of this product or materials made therefrom to provide a service, information, or data (e.g., DNA
sequence) to a third party in return for a fee or other consideration, or (5) resale of the product or its components or
derivatives, whether or not such product or its components or derivatives are resold for use in research. Academic,
Not-for-Profit, and For-Profit institutions must obtain a separate license from Lucigen Corporation to use this product
for any purpose other than those permitted above. It is the sole responsibility of the buyer to ensure that use of the
product does not infringe that patent rights of third parties.
If the purchaser is not willing to accept these use limitations, Lucigen Corporation is willing to accept return of the
product for a full refund. For information on obtaining a license, contact Lucigen Corporation, 2120 W. Greenview Dr.,
Middleton, WI 53562. Email: [email protected] Phone: 608-831-9011. Fax 608-831-9012.
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CLONESMART® Blunt Cloning Kits
Table of Contents
CloneSmart Kit Designations .......................................................................................... 4
Components & Storage Conditions ................................................................................. 4
CloneSmart Blunt Cloning Kit Description ....................................................................... 5
pSMART® Vectors ........................................................................................................... 6
E. cloni® Competent Cells ............................................................................................... 7
End Repair of Sheared DNA ........................................................................................... 7
Purification and Size Fractionation of DNA ..................................................................... 8
Sensitivity of DNA to Short Wavelength UV Light ........................................................... 8
Materials and Equipment Needed ................................................................................... 8
Detailed Protocol ............................................................................................................. 9
Preparation and Purification of Insert DNA...................................................................... 9
Ligation to the pSMART Vector....................................................................................... 9
Preparation for Transformation ..................................................................................... 10
Transformation .............................................................................................................. 10
Electroporation of E. cloni Electrocompetent Cells..................................................... 10
Heat Shock Transformation E. cloni Chemically Competent Cells ............................. 11
No Screening Required ................................................................................................. 13
DNA Isolation & Sequencing ......................................................................................... 14
References.................................................................................................................... 14
Appendix A: Media Recipes .......................................................................................... 15
Appendix B: Application Guide...................................................................................... 15
Appendix C: Abbreviated Protocol ................................................................................ 16
Appendix D: Vector Map, Cloning Site, and Sequencing Primers ................................. 17
Appendix E: Troubleshooting Guide.............................................................................. 18
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CLONESMART® Blunt Cloning Kits
CloneSmart Kit Designations
Several versions of the CloneSmart Blunt Cloning Kit are available. The Kits differ in number of
reactions, version of pSMART® vector (high or low copy; kanamycin or ampicillin resistance), and
E. cloni ® 10G Cells (electrocompetent; chemically competent; or no cells). Cells in the DUO format
contain 2 transformations per vial; the SOLO format is 1 transformation per vial. Please refer to
Appendix B: Application Guide for more information and recommended uses of the Kits.
Catalog numbers of vector and cell combinations
Vector
10G ELITE
Rxns Electrocompetent Cells
DUO
pSMART-HCKan
(High Copy)
pSMART-LCKan
(Low Copy)
pSMART-HCAmp
(High Copy)
10G
Chemically Competent
Cells
No Cells
DUO
SOLO
DUO
SOLO
40717-1
40719-1
40728-1
40730-1
---
10
40706-1
40708-1
20
40706-2
40708-2
40717-2
40719-2
40728-2
40730-2
40704-2
40
---
---
---
---
---
---
40704-4
10
40832-1
40834-1
40843-1
40845-1
40854-1
40856-1
---
20
40832-2
40834-2
40843-2
40845-2
40854-2
40856-2
40821-2
40
---
---
---
---
---
---
40821-4
10
40052-1
40054-1
40063-1
40065-1
40074-1
40076-1
---
20
40052-2
40054-2
40063-2
40065-2
40074-2
40076-2
40041-2
---
---
---
---
---
40041-4
40
pSMART-LCAmp
(Low Copy)
SOLO
10G SUPREME
Electrocompetent Cells
---
10
40311-1
40313-1
40322-1
40324-1
40333-1
40335-1
---
20
40311-2
40313-2
40322-2
40324-2
40333-2
40335-2
40300-2
40
---
---
---
---
---
---
40300-4
Components & Storage Conditions
The Ligation Components of the CloneSmart Kits are shipped in Container 1, which should be stored
at -20oC. If E. cloni Cells are ordered with the Kit, they are shipped in Container 2, which must be
stored at -80oC. Additional CloneSmart Ligation Components and E. cloni Competent Cells may be
purchased separately.
Store at -20°C
Container 1: CloneSmart Ligation Components
4X CloneSmart Vector Premix
Includes Buffer, ATP, and one type of ligation-ready
Vector:
pSMART-HCKan Premix or
pSMART-LCKan Premix or
pSMART-HCAmp Premix or
pSMART-LCAmp Premix
CloneSmart DNA Ligase (2 U/μl)
Positive Control Insert DNA (500 ng/μl lambda HincII)
CloneSmart Sequencing Primers (200 reactions each)
SL1 Primer (3.2 pmol/μl)
SR2 Primer (3.2 pmol/μl)
10 Reactions
25 μl
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20 Reactions 40 Reactions
1 x 50 μl
2 x 50 μl
12 μl
5 μl
24 μl
5 μl
2 x 24 μl
2 x 5 μl
200 μl
200 μl
200 μl
200 μl
2 x 200 μl
2 x 200 μl
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Store at -80°C
Container 2: E. cloni ® Competent Cells
STRAIN
Efficiency
Transformations
(cfu/μg pUC19)
Catalog #
E. cloni Electrocompetent Cells
E. cloni 10G SUPREME DUOs
> 4 x 1010
E. cloni 10G SUPREME SOLOs
E. cloni 10G ELITE DUOs
> 2 x 1010
E. cloni 10G ELITE SOLOs
12 ( 6 x 50 µl)
24 ( 12 x 50 µl)
60080-1
60080-2
12 ( 12 x 25 µl)
24 ( 24 x 25 µl)
60081-1
60081-2
12 ( 6 x 50 µl)
24 ( 12 x 50 µl)
60052-1
60052-2
12 ( 12 x 25 µl)
24 ( 24 x 25 µl)
60051-1
60051-2
E. cloni Chemically Competent Cells
E. cloni 10G
Chemically Competent DUOs
> 1 x 108
E. cloni 10G
Chemically Competent SOLOs
12 ( 6 x 80 µl)
24 ( 12 x 80 µl)
60107-1
60107-2
12 ( 12 x 40 µl)
24 ( 24 x 40 µl)
60106-1
60106-2
Medium and Controls
Recovery Medium
Store at -20 to -80°C
12 ( 1 x 12 ml)
24 ( 2 x 12 ml)
96 ( 8 x 12 ml)
------80026-1
*Supercoiled pUC19 DNA (1 ng/μl)
Store at -20 to -80°C
10 ( 1 x 10 µl)
----
YT Agar (powder)
----
Additional competent cells are available separately from Lucigen (please see our
web site: www. lucigen.com).
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CLONESMART® Blunt Cloning Kits
CloneSmart Blunt Cloning Kit Description
Lucigen’s CloneSmart transcription-free cloning technology (U.S. Pat. 6, 709, 861) is designed to
eliminate cloning bias and maximize cloning efficiency. The pSMART® vectors are supplied predigested, with blunt dephosphorylated ends, and are qualified to produce 99.5% recombinant clones
in typical experiments. The ultra-low background of empty vector (less than 0.5%) eliminates the
need to screen for recombinants and enables library construction from nanogram amounts of DNA.
Because no screening is required, CloneSmart technology eliminates the need for XGAL/IPTG and
removes the uncertainty of false negatives (light blue pUC colonies) and false positives (white
colonies that lack inserts). In contrast, conventional vectors utilizing the blue/white screen can
generate a dense background of blue colonies and many ambiguous “light blue” colonies, both of
which may contain inserts but are often discarded. The DNA contained in such clones is lost and
consequently thought to be “unclonable”, leading to gaps in sequence assemblies. Conventional
ampicillin-resistant plasmids are often surrounded by non-transformed “satellite” colonies, which
complicate colony picking and contaminate cultures. Growth of satellite colonies is completely
eliminated with the kanamycin-resistant pSMART vectors. Furthermore, the ampicillin-resistant
versions of pSMART vectors have been designed to reduce the growth of satellite colonies.
The kits are ideal for constructing shotgun libraries, for general purpose cloning, or for cloning blunt
PCR products, especially when amounts of target DNA are limited. The CloneSmart Blunt Cloning
Kits are convenient to use, containing pre-cut, dephosphorylated pSMART cloning vector premixed
with buffer and ATP, high-efficiency E. cloni ® Electrocompetent or Chemically Competent Cells, as
well as ligase, sequencing primers, and DNA controls. Kits without cells are also available.
Figure 1. Schematic diagram of the pSMART vectors. Ori, origin of replication; Amp, ampicillin
resistance gene; Kan, Kanamycin resistance gene; ROP, Repressor of primer (lowers plasmid copy
number). Approximate positions of sequencing primers and transcription terminators (T) are
indicated.
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CLONESMART® Blunt Cloning Kits
pSMART® Vectors
The pSMART vectors contain high- or low-copy replication origins and kanamycin or ampicillin
resistance (Figure 1). The unique design of these vectors eliminates transcription both into and out
of the insert DNA, reducing the cloning bias commonly found with standard plasmids. In
conventional plasmids, strong promoters are used to transcribe an indicator gene such as lacZα or a
negative selection gene such as ccdB. DNA cloned into these vectors can be lost due to plasmid
instability caused by transcription of toxic coding sequences, strong secondary structure, or other
deleterious features. The pSMART vectors do not use a promoter or an indicator gene, so
transcription across the insert is avoided. Conventional plasmids can also be lost due to fortuitous
transcription from inserts containing E. coli-like promoters, which can cause instability by transcribing
into essential regions of the vector. In pSMART vectors, strong transcription terminators flank the
cloning site to block this transcription (Figure 1), eliminating another cause of lost clones.
All pSMART vectors are supplied pre-cut with blunt, dephosphorylated ends (Figure 1). The copy
number of the pSMART-HCKan and -HCAmp vectors is similar to that of pUC plasmids (~300
copies/cell) and that of the pSMART-LCKan and -LCAmp vectors is similar to pBR322 (~20/cell).
The only difference between the high copy and low copy plasmids is the presence of the ROP gene
in the low copy versions, which inhibits plasmid replication. Blunt-ended, 5’-phosphorylated insert
DNA is ligated to the pSMART vector, transformed into competent cells, and spread on plates
containing kanamycin or ampicillin. pSMART transformants do NOT require additional screening
against colonies containing empty vector, as they typically are not present at detectable levels. The
GenBank accession numbers for the vectors are as follows: pSMART-HC, AF399742; pSMART-LC,
AY090111; pSMART-HCKan, AF532107; and pSMART-LCKan, AF532106.
E. cloni® Competent Cells
For maximum cloning efficiency, use of Lucigen’s E. cloni 10G Competent Cells is strongly
recommended. E. cloni 10G Competent Cells are E. coli strains optimized for high efficiency
transformation. They are ideal for cloning and propagation of BAC, cosmid, or plasmid clones. They
give high yield and high quality plasmid DNA due to the recA1 and endA1 mutations. They are also
phage T1-resistant (tonA mutation).
E. cloni 10G strains contain the inactive mcr and mrr mutations, allowing methylated genomic DNA
that has been isolated directly from mammalian or plant cells to be cloned without deletions or
rearrangements. The rpsL mutation confers resistance to streptomycin.
Lucigen’s CloneSmart Blunt Cloning Kits are available with the following preparations of E. cloni
Competent Cells:
E. cloni 10G SUPREME Electrocompetent Cells deliver > 4 x 1010 cfu/μg. Ideal for the most
demanding applications that require the greatest number of transformants, such as construction of
large, high complexity libraries or cloning difficult targets.
E. cloni 10G ELITE Electrocompetent Cells deliver > 2 x 1010 cfu/μg. Provide large numbers of
transformants from hard-to-clone fragments or limited DNA at a lower price than Supreme cells.
E. cloni 10G Chemically Competent Cells deliver > 1 x 108 cfu/μg. Unbeatable performance and
value for routine applications.
Genotype of E. cloni 10G: F- mcrA Δ(mrr-hsdRMS-mcrBC) φ80dlacZΔM15 ΔlacX74
endA1 recA1araD139 Δ(ara, leu)7697 galU galK rpsL nupG λ- tonA
• E. cloni Competent Cells are provided with supercoiled pUC19 DNA at a concentration of 1 ng/μl
as a transformation control. Dilute 1:100 in dH2O for transformation.
• Note: Use the provided Recovery Medium to resuspend the cells after
transformation. Use of TB or other media may result in lower transformation efficiencies.
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CLONESMART® Blunt Cloning Kits
End Repair of Sheared DNA
Because of their lack of cloning bias and pre-cut, blunt ends, the pSMART® vectors are ideal for
random shotgun cloning. This process typically entails a fragmentation step to randomly shear the
DNA, an end repair step to generate blunt ends, and a fractionation step to size-select the
fragments. Mechanical methods of DNA fragmentation (e.g., nebulization, sonication, hydrodynamic
shearing) are often preferred over enzymatic methods, as they are more random and reduce the
bias of sequencing projects (1). However, mechanical fragmentation results in a heterogeneous mix
of blunt and 3’- and 5’-overhanging ends that may not ligate efficiently. Successful library
construction requires a robust repair method to convert these ragged ends to blunt ends.
Lucigen has developed the DNATerminator® End Repair Kit (Cat. # 40035-1, 40035-2, and 40035-3)
to provide an efficient and convenient method for repairing DNA fragments. Use of the
DNATerminator End Repair Kit greatly improves construction of libraries from sheared DNA.
DNA needs to be relatively free of RNA before end repairing. Large amounts of contaminating RNA
will severely impair the efficiency of the end repair reaction, resulting in DNA with poor cloning
capability. We recommend the use of Lucigen’s RNAse I (Cat. # 30104-1 and 30104-2), which is an
exonuclease that breaks RNA down into nucleosides, to remove most of the residual RNA often
associated with DNA purification protocols. RNAse A, which is a site specific endonuclease, will not
degrade the RNA sufficiently and is not recommended.
For shotgun library construction, Lucigen recommends using the HydroShear™ instrument by
GeneMachines to randomly fragment DNA. Fragments generated by the HydroShear device are
repaired more efficiently than those produced through sonication or nebulization. It also generates a
tight distribution of fragments in any desired size range, increasing the proportion of DNA available
for cloning (2). The shearing results are also highly reproducible.
Purification and Size Fractionation of DNA
DNA must be purified from restriction or repair enzymes before ligation to pSMART vectors. Agarose
gel electrophoresis, which is commonly used to size fractionate DNA fragments, is sufficient for
purification. If end-repaired DNA is not fractionated by electrophoresis after repair or digestion, it
must be purified by phenol/chloroform extraction or binding to a DNA purification column to remove
the repair enzymes.
Sensitivity of DNA to Short Wavelength UV Light
DNA resolved on agarose gels is generally stained with ethidium bromide and visualized by
illumination with ultraviolet light. Exposure to short wavelength ultraviolet light (e.g., 254, 302, or 312
nm) can reduce cloning efficiencies by several orders of magnitude (Figure 2). Note that the
wavelength of most UV transilluminators, even those designated specifically for DNA visualization, is
typically 302 nm or 312 nm, and can cause significant damage to DNA.
Use a long wavelength (e.g., 360 nm) low intensity UV lamp and short exposure times when
isolating DNA fragments from agarose gels.
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100%
10%
1%
0.1%
0.01%
0.001%
No UV
30s 302nm
60s 302nm
120s 302nm 120s 360nm
Figure 2. Relative cloning efficiency of pUC19 after exposure to short or long wavelength UV
light. Intact pUC19 DNA was transformed after no UV exposure (“No UV”) or exposure to 302 nm UV
light for 30, 60, or 90 seconds (“30s 302nm, 60s 302nm,120s 302nm”) or to 360 nm UV light for 120
seconds (“120s 360nm”). Cloning efficiencies were calculated relative to un-irradiated pUC19 DNA.
Materials and Equipment Needed
The CloneSmart Blunt Cloning Kits supply most of the items needed to efficiently generate
recombinant clones. While simple and convenient, successful use of the CloneSmart Kit requires
proper planning for each step. Please read the entire manual and prepare the necessary equipment
and materials before starting. Following ligation, the following items are required for transformation:
• Electroporation apparatus and 0.1 cm cuvettes (for electrocompetent cells). Successful results
are obtained with cuvettes from BTX (Model 610) or BioRad (Cat. #165-2089). Users have
reported difficulties using E. cloni cells with Invitrogen cuvettes (Cat. # 65-0030).
• Water bath at 42 oC (for chemically competent cells).
• Wet ice.
• Sterile 17 x 100 mm culture tubes.
• YT agar plates containing ampicillin or kanamycin (powder included and see Appendix for
recipes).
Detailed Protocol
Preparation and Purification of Insert DNA
Generation of Blunt-Ended Fragments
DNA fragments created by digestion with blunt-cutting restriction enzymes (e.g., EcoRV or HincII)
can be used with the CloneSmart Blunt Cloning Kits without further processing. However, an endrepair reaction is required for cloning fragments generated by mechanical shearing (e.g. sonication
or hydrodynamic shearing), by PCR with polymerases having terminal transferase activity (e.g. Taq
or Tfl), or by restriction enzymes that leave 3’ or 5’ overhangs. The end-repair reaction must
generate blunt ends with 5’ phosphate groups.
For repairing mechanically sheared DNA, we recommend using Lucigen’s DNATerminator® End
Repair Kit, which has been optimized for this purpose. The DNATerminator End Repair Kit also very
efficiently removes 3’ or 5’ overhanging ends created by restriction digestion. Standard protocols for
end repair of restriction fragments, typically consisting of a series of steps incorporating a DNA
polymerase or exonuclease, may be used if desired.
For cloning PCR products with 3’ single base overhangs, we recommend using Lucigen’s
PCRTerminator® End Repair Kit to generate blunt phosphorylated ends. Alternately, PCR may be
carried out with a proofreading thermostable polymerase, such as Vent™ or Pfu polymerase, which
leaves blunt ends. After the reaction is complete, the PCR products must be phosphorylated with T4
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polynucleotide kinase. Kinase treatment of the PCR product is unnecessary if the PCR primers were
treated with kinase prior to the PCR or if they were synthesized with terminal 5’ phosphate groups.
Note: End-repaired or kinased fragments must be purified to remove the enzymes before
ligation to the pSMART vectors.
Purification of Repaired Fragments
If repaired or kinased fragments are subsequently fractionated by gel electrophoresis, no further
purification is necessary to remove the repair enzymes. Use of short-wavelength UV light (e.g., 254,
302, or 312 nm) must be avoided. After electrophoresis, DNA may be isolated using your method of
choice.
If the DNA is not fractionated by electrophoresis after end repair, it must be purified by extraction or
binding to a purification column to remove the repair enzymes. Heat denaturation is NOT sufficient to
inactivate the enzymes. Failure to completely remove residual enzymes may result in a large
background of empty vector clones or a greatly decreased ligation efficiency.
Ligation to the pSMART® Vector
In the CloneSmart ligation reaction, the pre-processed pSMART vector is ligated with blunt,
phosphorylated insert in a total volume of 10 μl. For library construction, we recommend using
300-500 ng of insert DNA in the size range of 1000 to 4000 bp. For cloning a single DNA species,
100-200 ng of insert is sufficient. Successful cloning can be achieved routinely with less than 100 ng
of insert, but use of low amounts of insert will result in significantly fewer transformants. The ligation
is performed as follows:
1. Briefly centrifuge the CloneSmart Vector Premix before use. Mix by gently pipeting up and down
several times.
2. Combine the following components in a 1.5-ml tube, adding the ligase last:
x μl Insert DNA (100-500 ng, blunt-ended, 5’-phosphorylated)
y μl H2O
2.5 μl 4X CloneSmart Vector Premix (pSMART vector, ATP, buffer)
1.0 μl CloneSmart DNA Ligase (2 U/μl)
10.0 μl total reaction volume
3. Mix by gently pipeting the reaction mixture up and down. Incubate at room temperature (21-25°C)
for 30 minutes. To obtain the maximum number of clones, ligation time can be extended to 2
hours. Optional control reactions include the following:
Positive Control Insert DNA
Vector Background
To determine the ligation and transformation efficiency with
a known insert, use 1 μl (500 ng) of the supplied HincIIdigested lambda DNA.
To determine the background of empty vector, omit Insert
DNA in the above reaction.
Preparation for Transformation
1. Prepare YT Agar from powder included with the cells. Colonies are small & grow slowly on LB.
2. Heat denature the ligation reaction at 70°C for 15 minutes.
3. Cool to room temperature for 15 seconds followed by 0-4°C for 15 seconds to condense water
vapor inside the tube.
4. Spin 1 minute at 12000 rpm to collect condensation and pellet precipitated material.
5. The sample is ready for transformation; precipitating the DNA is not necessary.
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Transformation
Most laboratory strains of E. coli (e.g., DH10B™, DH5α™, etc.) can be effectively transformed with
pSMART® ligation reactions. However, to ensure optimal cloning results, we strongly recommend the
use of Lucigen’s E. cloni ® 10G ELITE or 10G SUPREME Electrocompetent Cells. These cells yield
> 2 X 1010 or > 4 X 1010 cfu/µg of pUC19, respectively, to maximize the number of transformants. For
less demanding applications, E. cloni Chemically Competent cells should be used. However, the
number of clones will decrease in proportion to the competency of the cells. The following protocols
are provided for transformation of E. cloni Competent Cells.
Electroporation of E. cloni Electrocompetent Cells
E. cloni 10G ELITE and SUPREME Electrocompetent Cells are provided in 50 μl aliquots (DUOs),
sufficient for two transformation reactions of 25 μl each, or SOLOs (one transformation of 25µl).
E. cloni 10G ELITES are also available in 150 μl aliquots (SixPacks), sufficient for six transformation
reactions of 25 μl each.
Transformation is carried out in a 0.1 cm gap cuvette. Optimal settings for electroporation are listed
in the table below. Typical time constants are 3.5 to 4.5 msec.
Optimal Setting
1.0 mm cuvette
10 μF
600 Ohms
1800 Volts
Alternate Settings
(~ 20-50% lower efficiencies)
1.0 mm cuvette
25 μF
200 Ohms
1400 – 2000 Volts
Suggested Electroporation Systems:
Bio-Rad Micro Pulser #165-2100; Bio-Rad E. coli Pulser #165-2102; Bio-Rad Gene Pulser II #165-2105;
BTX ECM630 Electroporation System; Eppendorf Model 2510.
Optional transformation control reactions include electroporation with 10 pg of supercoiled pUC19
DNA (1 μl of a 1:100 dilution of the provided stock solution of pUC19).
To ensure successful transformation results, the following precautions must be taken:
• ESSENTIAL: After ligation, the reaction must be inactivated at 70°C for 15 minutes!
• Microcentrifuge tubes and electroporation cuvettes must be thoroughly pre-chilled on ice
before use. Successful results are obtained with cuvettes from BTX (Model 610) or BioRad
(Cat. #165-2089). Users have reported difficulties using E. cloni cells with Invitrogen cuvettes
(Cat. # 65-0030).
• The cells must be completely thawed on ice before use.
Transformation Protocol (Electrocompetent cells)
1. Have Recovery Medium and 17 mm x 100 mm sterile culture tubes readily available at room
temperature (one tube for each transformation reaction). Transformation efficiency may decrease
with the use SOC or other media.
2. Place electroporation cuvettes (0.1 cm gap) and microcentrifuge tubes on ice (one cuvette and
one tube for each transformation reaction).
3. Remove E. cloni cells from the -80°C freezer and place on wet ice until they thaw completely (1020 minutes).
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CLONESMART® Blunt Cloning Kits
4. When cells are thawed, mix them by tapping gently. Add 25 μl of E. cloni ® cells to the chilled
microcentrifuge tube on ice.
5. Add 1 μl of the heat-denatured CloneSmart Ligation reaction to the 25 μl of cells on ice. (Failure
to heat-inactivate the ligation reaction will prevent transformation.) Stir briefly with pipet tip;
do not pipet up and down to mix, which can introduce air bubbles and warm the cells. Use of
more than 2 μl of ligation mix may cause electrical arcing during electroporation.
6. Carefully pipet 25 μl of the cell/DNA mixture into a chilled electroporation cuvette without
introducing bubbles. Quickly flick the cuvette downward with your wrist to deposit the cells across
the bottom of the well. Electroporate according to the conditions recommended above.
7. Within 10 seconds of the pulse, add 975 μl of Recovery Medium to the cuvette and pipet up and
down three times to resuspend the cells. Transfer the cells and Recovery Medium to a culture
tube.
8. Place the tube in a shaking incubator at 250 rpm for 1 hour at 37°C.
9. Spread up to 100 μl of transformed cells on YT agar plates containing the appropriate antibiotic.
10. Incubate the plates overnight at 37°C.
11. Transformed clones can be further grown in TB or in any other rich culture medium.
Heat Shock Transformation of Chemically Competent cells
E. cloni 10G Chemically Competent Cells are provided in 80 μl aliquots (DUOs), sufficient for two
transformation reactions of 40 μl each, or SOLOs (one transformation of 40 µl).
Transformation is performed by heat shock at 42oC, followed by incubation on ice.
To ensure successful transformation results, the following precautions must be taken:
•
ESSENTIAL: After ligation, the reaction must be heat killed at 70°C for 15
minutes!
•
Ligation reactions performed with Lucigen’s UltraClone™ Kits can be used directly in
electroporation, without purification of the ligation products.
•
All microcentrifuge tubes must be thoroughly pre-chilled on ice before use.
•
The cells must be completely thawed on ice before use.
Transformation Protocol (Chemically Competent cells)
1. Chill sterile culture tubes on ice (17 mm x 100 mm tubes, one tube for each transformation
reaction).
2. Remove E. cloni cells from the -80°C freezer and thaw completely on wet ice (10-20 minutes).
3. Add 40 μl of E. cloni cells to the chilled culture tube.
4. Add 1 μl of the heat-denatured CloneSmart Ligation reaction to the 40 μl of cells on ice.
(Failure to heat-inactivate the ligation reaction will prevent transformation.) Stir briefly
with pipet tip; do not pipet up and down to mix, which can introduce air bubbles and warm
the cells.
5. Incubate on ice for 30 minutes.
6. Heat shock cells by placing them in a 42oC water bath for 45 seconds.
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7. Return the cells to ice for 2 minutes.
8. Add 960 μl of room temperature Recovery Medium to the cells in the culture tube.
9. Place the tubes in a shaking incubator at 250 rpm for 1 hour at 37°C.
10. Plate up to 100 μl of transformed cells on YT agar plates containing the appropriate antibiotic.
11. Incubate the plates overnight at 37°C.
12. Transformed clones can be further grown in TB or any other rich culture medium.
Table 1. Plating Transformed Cells
Reaction Plate
Experimental Insert
(500 ng per ligation)
Lambda HincII Insert (Positive Control)
No-Insert Control
(Vector Background)
Supercoiled pUC19 Transformation Control Plasmid (10 pg, AmpR)
μl/Plate
5, 20, & 100
5
50
2
Expected Results
The results presented below are expected when cloning 500 ng of intact, purified DNA fragments,
with blunt ends and 5’ phosphate groups, into Lucigen’s E. cloni 10G ELITE Electrocompetent Cells
(transformation efficiency > 2 x 1010 cfu/μg pUC19 DNA). The number of recombinant clones is
typically 1000-fold greater than the background of self-ligated pSMART vector. The background
number of empty pSMART vectors is constant (< 25 colonies per 50 μl of cells plated), unless kinase
is introduced as a contaminant. However, use of too little insert DNA, or insert DNA that is
improperly end-repaired, or modified DNA that is not repairable yields significantly lower
recombinant cloning efficiencies. Cloning AT-rich DNA and other recalcitrant sequences may also
lead to fewer colonies. With relatively few recombinant clones, the number of empty vector colonies
becomes noticeable. For example, if the Experimental Insert ligation reaction produces only 250
colonies from 50 ul of cells plated, then the 25 colonies obtained from 50 ul of the No-Insert Control
ligation will represent a background of 10%.
Use of competent cells with a transformation efficiency of less than 1 x 109 will severely compromise
the desired results, yielding less than 10% of the number of CFUs listed below.
Table 2. Expected Transformation Results from Electroporation
Reaction
CFU/Plate
Efficiency
pSmart-HC plus 500 ng lambda/HcII Insert
> 200
> 99.9% inserts
pSmart-LC plus 500 ng lambda/HcII Insert
> 50
> 99.9% inserts
No-Insert Control (Vector Background)
< 25
< 0.1% background
pUC19 Supercoiled Plasmid Control (10 pg) > 200
> 1 x 1010 cfu/µg plasmid
1. The above results were generated using Lucigen’s E. cloni 10G ELITE Electrocompetent Cells
(transformation efficiency > 2 x 1010 cfu/ug pUC19 DNA). Results with experimental DNA may
vary significantly, particularly with larger insert sizes, skewed base composition, encoded
peptides, etc. Use of chemically competent or other less efficient cells will result in proportionately
lower yields.
2. A 50 μl aliquot of the empty vector control reaction should produce < 25 colonies, representing
less than 0.1% background.
3. A 2 μl aliquot of transformed cells from the supercoiled pUC19 reaction (diluted into 90 μl of TB)
should yield > 200 colonies, or > 1 x 1010 colonies per μg plasmid.
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No Screening Required
For most applications, no additional screening for recombinant colonies is required, as the
CloneSmart system typically delivers >99.9% recombinant clones. Because the background of
empty vector transformants is extremely low, colonies can usually be picked at random for growth
and plasmid purification. However, some insert DNAs (e.g., those that are large or have unusual
base composition) may produce very few colonies, in which case screening by insert size may be
necessary to detect the relatively few recombinant plasmids among the small number of empty
vector clones.
DNA Isolation & Sequencing
Grow transformants in TB medium plus appropriate antibiotic (100 μg/ml ampicillin or carbenicillin for
pSMART-HCAmp or -LCAmp; or 30 μg/ml kanamycin for pSMART-HCKan or -LCKan.). Use
standard methods to isolate plasmid DNA suitable for sequencing. The pSMART-HC plasmids
contain the high copy number pUC origin of replication, yielding 20 – 80 μg of plasmid DNA per ml of
culture. The pSMART-LC plasmids contain the low copy number pBR322 origin of replication,
reducing plasmid yields to 0.5 – 1.0 μg per ml of cells. The E. cloni 10G Competent Cells are recA
endA deficient and will provide high quality plasmid DNA. The CloneSmart Kit is provided with the
sequencing primers SL1 and SR2. The sequence of the primers and their orientation relative to the
pSMART plasmid is shown in Appendix D.
References
1. Sambrook, J. and Russell, DW. Molecular Cloning: A Laboratory Manual (Third Edition). 2001.
Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York.
2. Thorstenson YR, Hunicke-Smith SP, Oefner PJ, Davis RW. 1998. An automated hydrodynamic
process for controlled, unbiased DNA shearing. Genome Res 8: 848-55.
3. Godiska R, Patterson M, Schoenfeld T, Mead DA. 2005. “Beyond pUC: Vectors for Cloning
Unstable DNA.” In DNA Sequencing: Optimizing the Process and Analysis. (J. Kieleczawa, ed.),
Jones and Bartlett Publishers, Sudbury, MA.
Appendix A: Media Recipes
YT+amp or YT+kan Agar Medium for Plating of Transformants. Add the YT Agar powder
provided with the kit to 500 ml of deionized water. Autoclave and cool to 55°C. Add the appropriate
filter-sterilized antibiotic to the cooled medium (e.g., 15 mg kanamycin for kanamycin-resistant
transformants; 50 mg ampicillin or carbenicillin for ampicillin-resistant transformants).
Temperatures of >55°C may destroy the antibiotics. Do NOT add antibiotics to hot media! Pour
approximately 20-25 ml per petri plate.
Per liter: YT is 8 g Bacto-tryptone, 5 g yeast extract, 5 g NaCl, 15 g agar, plus antibiotic. For
pSMART® -HCAmp or -LCAmp, prepare YT+amp agar medium by adding ampicillin or carbenicillin
to a final concentration of 50 mg/ 500 ml (equal to 100 μg/ml). For pSMART-HCKan and -LCKan,
prepare YT+kan30 agar medium by adding kanamycin to a final concentration of 15 mg/500 ml
(equal to 30 μg/ml).
YT Agar is available to purchase separately as 5 packets with catalog number 60025-1.
TB Culture Medium. Per liter: 11.8 g Bacto-tryptone, 23.6 g yeast extract, 9.4 g dipotassium
hydrogen phosphate (K2HPO4; anhydrous), 2.2 g potassium dihydrogen phosphate (KH2PO4;
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anhydrous), 0.4% glycerol. Mix all components except glycerol; autoclave and cool to 55°C. Add 8
ml filter-sterilized 50% glycerol per liter prior to using.
Growing Transformed Cultures. Colonies obtained from a pSMART transformation can be further
grown in TB or LB culture medium, containing the appropriate antibiotic (100 μg/ml ampicillin or
carbenicillin for pSMART-HCAmp or -LCAmp; 30 μg/ml kanamycin for pSMART-HCKan or -LCKan.).
Transformed cultures can be stored by adding sterile glycerol to 20% (final concentration) and
freezing at –70oC. Unused portions of the ligation reactions may be stored at –20 oC.
Appendix B: CloneSmart Application Guide
The series of CloneSmart Blunt Cloning Kits is available to accommodate any cloning situation. Use
of the kanamycin-resistant pSMART vectors is recommended, because ampicillin is readily
degraded by resistant clones. For routine applications, we recommend using the CloneSmart HCKan
Blunt Cloning Kit, containing the high copy number pSMART-HCKan vector. The copy number of
this vector is similar to that of pUC based vectors, yielding 20-80 ug of plasmid DNA per ml of
culture. For cloning toxic genes or more difficult DNA sequences, we recommend using the low copy
vector pSMART-LCKan. The plasmid yield is ~0.5-1 μg per ml culture.
For the most challenging inserts of up to 30 kb, including AT-rich DNA, repeated sequences, or other
regions with strong secondary structure, the pJAZZ® Linear vector in Lucigen’s BigEasy® v2.0 Linear
Cloning Kits provides unprecedented stability.
Use of the E. cloni ® 10G strain is essential for cloning inserts that may be methylated, such as
genomic DNA isolated directly from plant or mammalian cells, as this strain contains the inactive mcr
and mrr alleles [mcrA Δ(mrr-hsdRMS-mcrBC)]. The 10G SUPREME preparation of these cells is
recommended for cloning difficult or very small quantities of insert DNA.
Vector
Vector Name
pSMART-HC Kan
pSMART-LC Kan
pSMART-HC Amp
pSMART-LC Amp
pJAZZ®-OC
Copy #
High
Low
High
Low
Low-Mid
(Inducible)
Insert DNA Source
Cosmid,
Genomic
AT-Rich,
or cDNA
“Difficult”
Plasmid,
BAC, etc.
+
+
+
+
+
++
+
+
+
+
+
+
+
+
+++
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Desired Use
Digestion,
Subcloning, PCR, etc.
Sequencing
++
+
+
+
++
+
+
+
+
+
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Appendix C: Abbreviated Protocol
(Please see Manual for detailed instructions.)
Insert DNA Preparation
1. Generate target DNA fragments by shearing, restriction digestion, or PCR.
2. If necessary, repair the DNA ends to make them blunt, with 5’ phosphate groups.
3. Heat denature the repair reaction for 10 minutes at 70°C.
4. Purify DNA by phenol/chloroform extraction or gel electrophoresis. Do NOT use 256, 302,
or 312 nm UV light to visualize the DNA.
Ligation
1. Briefly centrifuge and gently mix the CloneSmart Vector Premix.
2. Combine the following components in a 1.5-ml tube. Add ligase last.
x μl Insert DNA (100-500 ng, 1 – 4 kb, blunt-ended, 5’-phosphorylated)
y μl H2O
2.5 μl 4X CloneSmart Vector Premix (pSMART® vector, ligation buffer, ATP)
1.0 μl CloneSmart DNA Ligase (2 U/μl)
10.0 μl total reaction volume
3. Incubate 30 minutes at room temperature. (Incubate 2 hours for maximum number of clones.)
4. Heat denature the ligation reaction 15 minutes at 70°C.
5. Cool 15 seconds at room temperature and 15 seconds on ice.
6. Spin 1 minute at 12,000 rpm.
Transformation (USE ONLY ELECTROCOMPETENT CELLS FOR ELECTROPORATION
AND CHEMICALLY COMPETENT CELLS FOR HEAT SHOCK TRANSFORMATION!)
1. Place Recovery Medium at room temperature.
2. Chill electroporation cuvettes, 1.5 ml microfuge tubes, and sterile culture tubes on ice.
3. Thaw E. cloni Electrocompetent Cells or Chemically Competent Cells on wet ice. Pipet 25 μl of
Electrocompetent cells into a pre-chilled 1.5 ml tube on ice or 40 μl Chemically competent cells into a
pre-chilled 17 mm x 100 mm culture tube on ice.
4. Add 1 μl of heat-treated ligation reaction to an aliquot of chilled cells on ice.
Electroporation
5. Pipet 25 μl of the cell/DNA mixture
to a chilled electroporation cuvette.
6. Electroporate. Immediately add
975 μl of room temperature Recovery
Medium. Place in culture tube.
Heat Shock Transformation
5. Incubate 30 minutes on ice.
6. Incubate 45 seconds at 42 oC; then
2 minutes on ice. Add 960 μl of room
temperature Recovery Medium to the
culture tube.
7. Shake at 250 rpm for 1 hour at 37°C.
8. Spread up to 100 μl per plate on YT agar plates containing the appropriate antibiotic. Incubate
overnight at 37°C.
Colony Growth
1. Pick colonies at random and grow in TB medium containing the appropriate antibiotic.
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Appendix D: Vector Map, Cloning Site, and Sequencing Primers
The pSMART® vectors are supplied predigested, with blunt, dephosphorylated ends. Transcriptional
terminators border the cloning site to prevent transcription from the insert into the vector. Another
terminator at the 3’ end of the ampicillin or kanamycin resistance gene prevents this transcript from
reading into the insert DNA.
The cloning sites and sequencing primers are identical for pSMART-HCAmp, -LCAmp, -HCKan, and –
LCKan. The sequences of the SL1 and SR2 primers are as follows:
SL1: 5’–CAG TCC AGT TAC GCT GGA GTC–3’
SR2: 5’–GGT CAG GTA TGA TTT AAA TGG TCA GT–3’
The GenBank accession numbers of the pSMART vectors are as follows:
pSMART-LCKan: AF532106
pSMART-LCAmp: AY090111
pSMART-HCKan: AF532107
pSMART-HCAmp: AF399742
SL1 Primer
EcoRV Hind III* EcoRI
Insert DNA
CAGTCCAGTTACGCTGGAGTCTGAGGCTCGTCCTGAATGATATCAAGCTTGAATTCGTT...
GTCAGGTCAATGCGACCTCAGACTCCGAGCAGGACTTACTATAGTTCGAACTTAAGCAA...
Insert DNA
EcoRI XbaI EcoRV
SwaI
...GACGAATTCTCTAGATATCGCTCAATACTGACCATTTAAATCATACCTGACCTCCATAGCAGAAAG
...CTGCTTAAGAGATCTATAGCGAGTTATGACTGGTAAATTTAGTATGGACTGGAGGTATCGTCTTTC
SR2 Primer
*The Hind III site is NOT unique in the pSMART-HCKan and -LCKan vectors. Another Hind III site is
present in the kanamycin resistance gene.
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Appendix E: Troubleshooting Guide
Problem
Very few or no
transformants
Probable Cause
Solution
Inefficient end repair.
Contaminating enzymes in
ligation reaction.
No DNA, degraded DNA, or
insufficient amount of DNA.
Ligation reaction failed.
Inadequate heat
denaturation of ligation
reaction.
Loss of DNA during
precipitation.
Incorrect recovery media.
Improper electroporation
conditions.
Addition of XGAL/DMSO to
competent cells.
Incorrect amounts of
antibiotic in agar plates.
High background
of transformants
that do not contain
inserts.
Wrong antibiotic used.
Contaminating
oligonucleotides in the
ligation reaction.
Contaminating enzymes in
ligation reaction.
Incorrect amount of
antibiotic in agar plates.
Unstable DNA Inserts
Check the insert DNA for self-ligation by gel
electrophoresis. Repeat end repair if necessary.
Heat-denature end repair reaction or restriction
digest 10 minutes at 70°C. Purify DNA by extraction
or adsorption to matrix.
Check insert DNA by gel electrophoresis.
Determine concentration of insert and add the
correct amount. Use the supplied control insert to
test the system.
Check the insert DNA for self-ligation by gel
electrophoresis. Repeat end repair if necessary.
Be sure insert DNA is phosphorylated. Use the
supplied control insert to test ligation reaction.
Be certain to heat denature for 15 min at 70°C.
Skipping this step may lower the number of
transformants by 2-3 orders of magnitude.
DO NOT precipitate DNA after ligation reaction. It is
not necessary with this protocol and these cells.
Use TB (Terrific Broth) for outgrowth after
transformation of electrocompetent or chemically
competent cells.
Use BTX or BioRad electroporation cuvettes with a
gap of 0.1 cm.
Pre-chill cuvettes on ice.
Add the 1 μl of DNA to 25 μl of pre-aliquotted cells
on wet ice; DO NOT add the cells to the DNA.
DO NOT add additional compounds to competent
cells, as they are fragile.
Add the correct amount of Ampicillin/Carbenicillin or
Kanamycin to molten agar at 55°C before pouring
plates (see Appendix A). DO NOT spread antibiotic
onto the surface of agar plates.
Gel purify inserts before cloning. Use multiple
methods of DNA purification to remove small
fragments.
Purify DNA after DNA End Repair reaction. DO
NOT add T4 DNA Kinase to the ligation reaction.
DO NOT spread antibiotic onto the surface of agar
plates. Add the correct amount of kanamycin or
ampicillin/carbenicillin to molten agar at 55°C
before pouring plates (see Appendix A).
Use the BigEasy® v2.0 Linear Cloning Kit for
maximum clone stability.
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